Question about Samsung S65UA

You can use both, and the package contains a suitable USB-C. Note that not every USB-C cable works, it has to be certified (don’t remember the exact standard).

Although HDMI works as well, I prefer USB-C because with a single cable you get image, sound(*), power, ethernet(*) and USB. Basically it’s a docking station.

(*) if you connect speakers and network cable respectively to the monitor